Drying apparatus

ABSTRACT

A drying apparatus which has a slit for ejecting an air jet, a mechanism for carrying a material so that the surface of the material being dried passes near the slit, and blade plates extending generally in parallel with the surface being dried in the direction of movement of the material by the slit, and in the direction opposite thereto.

United States Patent 1191 Sato et al. Apr. 23, 1974 [54] DRYINGAPPARATUS 3,344,729 /1967 Kitrosser 95/89 R 3,440,944 4/1969 E d ann et1... 95/89 R [75] Invemors: Masamch' sat; I501 Takahash" 3,477,35611/1969 1x2 7 3 61 95/89 R x v both of Asaka, Japan 3,372,630 3/1968Schmidt 95/89 R x 3,437,030 4/1969, Mastrosimone et al 95/89 R X [73]Asslgnee' 2" Photo j 3,559,558 2/1971 Hamlin et al. anagawa 3,405,627l0/l968 Day et al 95/94 R [22] Filed: Oct. 12, 1971 Prima Examiner-FredL. Braun 584 W [2]] App] No Attorney, Agent, or FirmJ. T. Martm; GeraldJ. Ferguson, Jr.; Joseph J. Baker Foreign Application Priority Data Oct.12, 1970 Japan; -101349 52 us c1. 34/160, 95/89 R A drying apparatusWhih has 9 Slit for ejecting an air 51 1m. 01 F26b 13/20, 003d 3/12 j amechanism r y g a material so that the [58] Field 6: Search 95/89 R, 89A, 94 R; Surface of the material being dried Passes near the slit, 3 5 10 and blade plates extending generally in parallel with the surfacebeing dried in the direction of movement 5 References Cited of thematerial by the slit, and in'the direction oppo- UNITED STATES PATENTSEloranta 95/89 R X site thereto.

4 Claims, 7 Drawing Figures mansnmza m4 3805L409 mm 1 n? 2 FIG. I

PRIOR ART DRYING APPARATUS BACKGROUND OF THE INVENTION This inventionrelates to an apparatus for drying material with an air stream and, inparticular for drying an electrophotographic material or silver halidephotographic material.

The conventional drying apparatus using an air jet has manydisadvantages as will be described with reference to the conventionalapparatus shown in FIG. 1. In FIG. 1, which shows a longitudinalsectional side view of the conventional drying apparatus for sheets orweb material using an air stream, there is shown a material to be driedsuch as an electrophotographic material moistened upon treating by aliquid developing process or silver halide photographic materialmoistened with water after developing treatment. There is also shown anair supply pipe 11, an air jet injection slit 12, the place 13 directlyunder the slit 12 where the air jet is strongest, an air stream 14indicating that the ejected air jet is expanding, and a drive roller 16for driving the material 10 to be dried in the direction designated byan arrow 15. The air is fed into the air supply pipe by an aircompressor or fan. When the roller 16 is rotated clockwise, the material10 is driven in the direction designated by arrow 15. The liquid whichmoistens the surface of the material 10 is swept in the directiondesignated by arrow 17 by the air jet. It is common that a very thinliquid is retained on the surface of the material 10 even if the liquidon the surface of the material 10 is swept by the air jet. However, thisthin liquid film is dried and evaporated by the air jet. This thinliquid film is retained in the event that the surface of the material 10is moistened with a wettable liquid. For example, the thin liquid filmis retained when a material having a hydrophilic surface is moistenedwith water or when a material having an oilphilic surface is moistenedwith oil. On the contrary, the thin liquid film is not retained when thehydrophilic surface is moistened with oil or when the oilphilic surfaceis moistened with water.

In the apparatus shown in FIG. I, the speed of the air jet is very highat the place 13 directly under the slit 12, but the air stream canfreely expand in the space away from the place 13 as shown by numeral14, and accordingly the speed of the air jet becomes abruptly small. Asa result, the air stream away from the place 13 has a small capabilityto sweep the liquid on the surface of the material 10 and also has smallcapability to dry the liquid film retained on the surface of thematerial 10. In other words, the drying speed is low. Therefore, thespeed for driving the material 10 in the direction designated by arrowcannot be substantially increased. The simplest method for increasingthe drying speed in the apparatus shown in FIG. 1 is to increase the airamount supplied into the pipe 11 thereby increasing the speed of the airjet from the slit 12. However, it incorporates the followingdisadvantages.

First in order to increase the air supply amount, the capacity of theair compressor or the fan must be increased with the result that the airsupplying device becomes large. Second, if the speed of the air jetbecomes high, the sound generated at the air jet injection slit 11 isenhanced to introduce a large noise within the drying apparatus. Third,the speed of the air stream at the place 13 directy under the slitbecomes locally very strong with the result that it undesirably affectsthe material. For example, it is thought that the toner image formed onthe surface of the electrophotographic material can be damaged. It iswell known that the toner image obtained by the liquid developingprocess is mechanically very weak before it is fixed, particularly whileit is moistened, and thus tends to be broken. Therefore, if anexcessively high speed air jet is used, the toner image tends to bedamaged. Accordingly, it is desirable to avoid an increase in the speedof the air jet.

SUMMARY OF THE INVENTION DETAILED DESCRIPTION OF PREFERRED EMBODIMENTSThese and other objects, features and advantages of this invention willbecome apparent from the following description taken in conjunction withthe accompanying drawings, in which:

FIG. 1 is a longitudinal sectional side view of the conventional dryingapparatus for sheets or web material using an air stream;

FIGS. 2 to 7 show longitudinal sectional side views of the embodimentsof the drying apparatus of this invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference is now made tothe drawings, particularly to FIGS. 2 to 7, which show the embodimentsof this invention.

In FIG. 2, there is shown the essential part of one embodiment of thedrying apparatus of the invention in principle.

Reference numerals 20 and 21 illustrate blades extended at both sides ofa slit 12, extending generally in parallel with the surface of thematerial 10. The lengths of the blades 20 and 21 in the directiondesignated by arrow 15 may be properly selected, but the larger the sizeof the blades, the faster the speed. However, when the drying apparatusis contemplated to be compact, this length may be properly designed inrelation with the size of the apparatus. The widths of the blades 20 and21 perpendicular to the arrow 15 may be generally similar to the lengthof the slit perpendicular to the arrow 15. If the material 10 is drivenin the direction designated by arrow 15 under the slit 12, the air jetejected from the slit 12 passes through the gaps 22 and 24 between thematerial 10 and the blades 20 and 21 to be expanded in the space at theend of the blades as shown by 23 and 25 in FIG. 2. As shown in FIG. 2,the air jet discharged from the slit 12 does not expand at once in thespace, but expands after passing the long passages 22 and 24. Therefore,in comparison with the apparatus shown in FIG. 1, the time the airstream at high speed contacts with the surface of the material 10becomes long with the result that the capability to sweep the liquidmoisture on the surface of the material 10 and to dry the thin liquidfilm retained on the swept surface become quite large.

Referring now to FIG. 3, which shows the section of the essential partof the embodiment desirable in this invention, numerals 30 and 31 show apair of feed rollers. The roller 30 has flanges at both ends thereof,and the material 10 is driven interleaved between the flanges and theroller 31. The roller surface 35 inside ther flange of the roller 30does not contact the material 10. This condition is particularlyimportant in case the material 10 has a toner image on anelectrophotographic material. That is, it prevents the toner image frombeing damaged by minimizing contact with the roller 30. The roller 32maintains the distance between the surface of the material 10 and theslit constant similar to the roller 16 in FIG. 2. The rollers 33 and 34are a pair of feed roller having the same function as that of therollers 30 and 31, respectively. The roller 33 has flanges at both ends,and 36 shows the area inside the flanges. The material isengaged withthe flanges of the roller 33 and the roller 34 and fed in the directiondesignated by the arrow 15. The blades and 21 extend front and rear onboth sides thereof from the slit l2 and contact the rollers and 33,respectively in order to prevent the air from leaking at the gap betweenthe blade 20 and the roller 30 or between the blade 21 and the roller33. In practice, the air may be leaked. The air supplied to the pipe 11is ejected from the slit 12 to pass the gaps 22 and 24, and furtherthrough the gaps between the rollers 30 and 31, 33 and 34 and expandedin the free space as shown by 37 and 38 in the drawing. The apparatusshown in FIG. 3 is particularly proper for the material 10 being insheet state. The dimensions and an example of the operation will now bedescribed with concrete reference to numerals thereof as this embodimentof the apparatus. The outer diameters of the rollers 30 to 34 are 18 mm,the inside diameter of the rollers 30 and 33 and flanges or the diameterof the rollers and 36 in FIG. 3 are l6.6 mm, and accordingly thethickness of the flange is 0.7 mm, the material of the rollers 30 to 34being all stainless steel. The inner diameter of the pipe 11 is 14 mm,the thickness thereof 1.5 mm and the material thereof brass. The widthof the slit 12 is 1 mm, the gap between the blades 20 and 21 and thesurface of the material 10 being 2 mm. The length of the lateraldirection rightward and leftward of the blades 20 and 21 in the drawingare both 20 mm. The material 10 was driven at a speed of 5 cm per secondin the direction designated by arrow 15, and the air supply amount tothe pipe 11 was 2,800 liters per minute. However, in order to preventthe air from being leaked laterally (vertically in the drawing), sidewalls are provided at both sides. Under such conditions, theelectrophotographic material is preferably preferably. When the blades20 and 21 were not provided, the drying was insufficient.

FIG. 4 shows the section of the essential part of another preferredembodiment of the drying apparatus of this invention. Numeral 40 shows adrive roller for driving a web 41 around the roller, 41 a developercontainer, 43 a developing liquid filled therein, 44 and 45 are bladesextended at both sides front and rear of the slit 12 parallel with theperiphery of the roller 40, and

46 is a roller for changing the direction of the web. The air ejectedfrom the slit passes through the gaps 47 and 48 to be expanded in thespace as shown by 49 in the drawing. When the width of the slit l2, gaps47 and 48, and driving speed of the web are selected similar to theembodiment in FIG. 3, the preferred result is obtained.

FIG. 5 shows the section of the essential part of a further embodimentof the drying apparatus of this invention. The apparatus shown in FIG. 5has no corresponding blade 21 in FIG. 3. Instead, the pipe 11 contactsthe roller 33 so as to reduce the air from being leaked between the gapof the pipe 11 and the roller 33. The other functions and parts are thesame as those in the embodiment shown in FIG. 3. The object of thisinvention will be effectively performed by the apparatus which has onlyone blade at one side of the slit 12 as shown in FIG. 5. However, it isrecognized that the embodiment of FIG. 3 results in a better effect thanthat of FIG. 5.

FIG. 6 is the section of the essential part of still another embodimentof this invention. Numeral indicates flanges provided at both ends ofthe pipe 61 similar to the pipe 11 shown in FIG. 3, the flanges beingfreely rotatable. Numeral 62 is a slit provided at the lower end of thepipe 61 corresponding to the slit 12 in the drying apparatus shown inFIG. 3. Numerals 63 and 64 are blades provided at both ends of the slit62 corresponding to the blades 20 and 21 in FIG. 3. In the embodimentshown in FIG. 3, the material 10 is depressed adjacent the roller 32 bythe airjet ejected from the slit 12 but in FIG. 6, the material 10 isengaged by the flanges 60 and roller 32. Consequently, when the material10 arrives under the slit, the possibility that the material 10 willprevent the turbulence of the air stream from passing through remote.More particularly, the drying apparatus in FIG. 6 is the embodimentwhere the passage of the material 10 becomes stable.

FIG. 7 shows the section of the essential part of still anotherembodiment of the drying apparatus of this invention. This apparatus hassymmetrical structure to the material 10 for drying both the front andrear surface of the material at the same time.

What is claimed is:

l. A drying apparatus comprising (1 at least one air supply meansincluding (a) a slit for ejecting an air jet onto a material having adeveloped image on the surface to be dried, said slit being disposedtransverse to the direction of movement of the material, has beeninserted. and (b) two blade plates respectively extending from the sidesof the slit generally across the width of and in parallel with thesurface to be dried, and two pairs of feed rollers for carrying thesurface to be dried past the said slit where each pair is disposed onopposite sides of said material and on opposite sides of said slit, thefeed rollers on the same side of said material as said blade plateshaving flanges at both ends thereof which contact said material at theapproximate edges thereof, to thereby prevent said material fromcontacting said blade plate so that said image cannot be damaged bycontact with said blade plates, and where said blade plates contact thefeed rollers which are on the same side of said material as themselvesto prevent the passage of said air jet therebetween.

2. A drying apparatus as in claim 1 where said at least one airsupplying means includes a rotatable flange disposed at each end of saidslit to prevent said material from contacting said blade.

3. A drying apparatus as in claim 1 including a second air supply meanssymmetrically disposed on the side of said material opposite said atleast one air supply means.

4. A drying apparatus comprising (l) at least one air supply meansincluding (a) a slit for ejecting an air jet onto a material having adeveloped image on the surface to be dried, said slit being disposedtransverse to the direction of movement of the material, has beeninserted. and (b) at least one blade plate extending from one side ofthe slit generally across the width of and in parallel with the surfaceto be dried, and (2) at least one pair of feed rollers for cayying thesurface to be dried past the said slit, said pair of feed rollers beingdisposed on opposite sides of said material and adjacent one side ofsaid slit the feed roller on the same side of said material as saidblade plate having flanges at both ends thereof which contact saidmaterial at the approximate edges thereof to thereby prevent saidmaterial from contacting said blade plate so that said image cannot bedamaged by contact with said blade plate, and where said air supplyingmeans includes a rotatable flange disposed at each end of said slit toprevent said material from contacting said blade.

1. A drying apparatus comprising (1), at least one air supply meansincluding (a) a slit for ejecting an air jet onto a material having adeveloped image on the surface to be dried, said slit being disposedtransverse to the direction of movement of the material, has beeninserted. and (b) two blade plates respectively extending from the sidesof the slit generally across the width of and in parallel with thesurface to be dried, and two pairs of feed rollers for carrying thesurface to be dried past the said slit where each pair is disposed onopposite sides of said material and on opposite sides of said slit, thefeed rollers on the same side of said material as said blade plateshaving flanges at both ends thereof which contact said material at theapproximate edges thereof, to thereby prevent said material fromcontacting said blade plate so that said image cannot be damaged bycontact with said blade plates, and where said blade plates contact thefeed rollers which are on the same side of said material as themselvesto prevent the passage of said air jet therebetween.
 2. A dryingapparatus as in claim 1 where said at least one air supplying meansincludes a rotatable flange disposed at each end of said slit to preventsaid material from contacting said blade.
 3. A drying apparatus as inclaim 1 including a second air supply means symmetrically disposed onthe side of said material opposite said at least one air supply means.4. A drying apparatus comprising (1) at least one air supply meansincluding (a) a slit for ejecting an air jet onto a material having adeveloped image on the surface to be dried, said slit being disposedtransverse to the direction of movement of the material, has beeninserted. and (b) at least one blade plate extending from one side ofthe slit generally across the width of and in parallel with the surfaceto be dried, and (2) at least one pair of feed rollers for cayying thesurface to be dried past the said slit, said pair of feed rollers beingdisposed on opposite sides of said material and adjacent one side ofsaid slit the feed roller on the same side of said material as saidblade plate having flanges at both ends thereof which contact saidmaterial at the approximate edges thereof to thereby prevent saidmaterial from contacting said blade plate so that said image cannot bedamaged by contact with said bladE plate, and where said air supplyingmeans includes a rotatable flange disposed at each end of said slit toprevent said material from contacting said blade.